Apparatus for film printers



Dec. 15, 1931. J. R. MALCOLM ET AL APPARATUS FOR FILM PRINTERS Filed May17 192 2 Sheets-Sheet l INVENTOR s (calm; encgJ/j HIIIIII III] 056 a B 7Q) ATTORNEY Dec. 15, 1931. J. R. MALCOLM ET AL APPARATUS FOR FILMPRINTERS 2 Sheets-Sheet 2 s Jr Filed May 17, 1927 INVENTOR JosebkRlfalco Jo/zn, 5 5166220 6, aim WW Patented Dec. 15, 1931 UNITEDSTATES PATENT OFFICE JOSEPH B. MALCOLM AND JOHN L. SPENCE, JR, OF NEWYORK, N. Y.; SAID 'SPEN'CE AB- SIGNOR TO SAID IALCOLH APPARATUS FORFIILI PRINTERS Application filed Kay 17, 1827. Serial No. 192,188.

Our present invention relates to an improved apparatus for use inprinting photo aphic positives from negative films.

. n its present embodiment, and as herein 5 disclosed one preferred formof its use is in adapting it to printing from a line of continuousnegatives, such as a moving picture fihn, although, obviously its useneed not be so limited.

As is well known, in this class of work, a negative (strip,) film variesgreatly in its density, successively, throughout its length,

' so that in printing positives therefrom, the

positives themselves varyin like manner to 5 the detriment of goodprojection thereafter due to these irregularities.

This has been met heretofore, by providing for a viewing a paratus forthe negative film whereby a skllled operator may examine 20 suchnegative film, and by pure skill and judgment, predetermine the latercontrol of the light in the positive printing machine by the printingoperator, this being noted by the skilled operator and indicated by 2cards to accompany the negative film, and by notchin the film itself atsuch points along the lm where such light control is generally indicatedb the card, and locally indexed on and for t e variably dense portionsof the film, thereby to permit the printing of a positive therefrom inwhich the extremes of density are somewhat averaged and the positivethereby improved for prov jection. This method leaves much to be de- 35sired, as perfection of the finished positive is subject to the more orless guess and skill of the viewing operator.

Our invention is devised to embody an apparatus whereby such densityvariations in negative films are met, and produce positives of aperfection of eveness of density regardof any density change in thenegative varying the printing of an even positive from an unevennegative, by using a fixed or predetermined amount of control light, thevariations of which, in passing through the uneven negative cause aninverse action of the printing means, thereby to average the dens- Theforegoing is, further, accomplished by ity of the printed ositive.Inasmuch as this. operation is,'in su stance, purely mechanical asidefrom the electrical features thereof, it is, therefore, susceptible ofproducing a constant densit of printed product, involving no human s illor guesswork,-regardless of general or local density changes onthenegative film.

Due to the details of apparatus structures the films, (negative andpositive) may be run at much faster rates of speed, in printing, thanhas heretofore been possible, this feature having a number of obviouspossibilities, such as lowered cost of printing, less exposure of filmto heat of printing lamp, with consequent reduction of hazards.

In the drawings Fig. 1 is a sectional view of one form of our apparatustaken on line 11 Fig. 2 looking in the direction of the arrows; Fig. 2is a side view thereof, Fig. 3 is a fragmentar view, similar to Fig. 1,showing a modi ed form of density control of the printing light. Ourapparatus comprises a casing 1, generally enclosing the apparatus, andis provided at one side thereof with a plurality of removable doors 2and 3, all of which permit access to the film reels 4, 5, 6 and 7, forintroduction and removal of the filled and empty reels during operation.These reels are,mounted in the casing in the customary manner, uponspindle 8, 9, 10 and 11, these mountings, reels and general featuresthereof being substantially of well known and eneral use in this art,and, it is though, nee not be further described.

The main mechanism herein is driven, in a continuous manner, by means ofan electric motor 12, Fig. 2, mounted, preferably upon the outside ofthe casing 1 being suitably located upon a bracket 13, as shown. Themotor shaft 14 mounts a bevel gear 15, which in turn drives a mate car16 rigidly afiixed to a vertical worm shaft 17 rotatably supportedagainst the casing wall in bearings 18 and 19. .The worm shaft mounts,at its opposite ends worms 20 and 21, which in turn engage worm wheels,not shown which are afiixed to and drive the film feeding sprockets 22and23, which are rotatably mounted at right angles to the worm shaft 17,but within the casing 1,

and upon a bearing or assembly plate 24, which is firmly aflixe to theinside wall of the casing 1 by means of screws 25.

Mounted upon the bearing plate 24, which is arran ed to support most ofthe mechanism hereina er to be described, is a film gate, generally by26, comprising a pair of upper and lower tensioned film idler rolls .27and 28, which, as in usualpractice are arranged to be movable to threadthe film through the gate and to guide the film into and out of theprinting position adjacent the gate.

For convenience the gate aperture 29 is housed atits rear, as at 30,thereby to enclose the printing light 31 and condensing reflector 31 andthe mounts therefor in a light proof manner.

In the present instance,-and for clarity only, we have located thenegative density sensing mechanism 32, at a distance from its truelocation, in Figs. 1 and 3, and it comprises in its essence, an enclosedhousing 33 containing an electric li ht 34 of suitable candle power withits re ector-condenser 35 and their respective mountings, the housinghaving ,an aperture at 36 to permit the condensed reflected light'raysto pass across the film path to a photo-electric cell 37 of knowndesign, this cell having the fimction of passing electric currenttherethrough inaccordance with thelight variations that fall upon it,this cell being housed in a casing 38 which is apertured'as' at 39 tocoordinate with the aperture 36 of the casing 33.

In actual practice the last above described negative sensing mechanismis actually closer to the film gate aperture 29, so as to act withgreater rapidity upon the printer mechanism "with a minimum ofconsecutive or successive pictures between the density sensing position32 and the film printing gate 29, for obvious reasons.

As a means for causing coordination between the sensing and printinmechanisms above described, we have provi ed an electri- 4 callyactuated control'for the printing light comprising an electro magnet 37,Fig. 1 in the central core of which is mounteda lunger 38 the upper endthereof being provi ed with an eye bar-pivot or oke 39", the said yokebeing pivotally attac ed to a movable resistance lever 40, one end ofwhich is pivoted as at 41 for permitting the lever to move across anelectrical resistance '42. The plunger 38 is held, normally in adownward positlon in the core of the solenoid by means of a coil sourceof electric current B, by wires C, D, E,

G, resistance 42 lever 40'and wire If, and the amount of current passingthrough 31 is 7 in accord with the position-of lever 40 upon theresistance 42. The density of light 34 is connected to the source ofelectric current B, by means of wires H, D, E and there being noresistance interposed in this circuit, so that the brilliance of thislamp 34 is constant. The photo-electric cell 37 is interpolated into andcontrols the flow of current from B to the printing light 31 throughwires E, I, J, through solenoid 37, and wires K and D to source B. y v

In operation an upper reel 4 is loaded with an unexposed positive filmM, and positioned as shown, and another reel 6 is loaded with a negativefilm N, positioned as shown, and both films are threaded down throughthe film gate 26, and from thence to their respective reels '5 and 7 asshown. Upon starting the drive means 12, the sprockets 22-23 cause boththe films to simultaneously feed past the gate 26, and the lights 31'and 34 are lighted. The light 34, being constant passes through thenegative film N, arid strikes the photo electric cell 37 whereupon thelight striking the same, passes a minimum or maximum current to li ht31, according to the varying densities o the negative 'film passingthrough housing 33, thereby decreasing or increasing the brilliance ofthe print ing light 31'.

Thus, a heavy or dense section of negative film would pass a minimumamount of current through coil 37' thereby permitting spring 38 to pulldown plunger 38, cutting down the resistance in the printing lightcircuit, and increasing the actinic light, through this dense portion ofnegative film.

Conversely, when a less dense portion or.-

section of negative film passes through housing 33, a greater amount oflight passes to photo-cell 37, passes a great amount of current throughcoil 37, which in turn throws the plunger 38 upward, thereby increasingresistance in the printing light circuit and causing printing light 31'to receive less ourlight, thereby printing the positive lighter.

Thus it will be observed that a dense por-j t1on of thenegative'increases, and a lighter,

or less dense portion decreases the actinic light supplied at theprinting point to the positive fihn, and that the accompanying increaseor decrease of actinic power to the pos1t1ve film is automaticallycontrolled by the varying densities of the negative film itself toaverage the tone, exposure, and density of thepositive film.

By this means, and under proper print-ing light conditions, anynegative; film of extremes in density is utilized to produce a positiveof even density, and at a more rapid rate of speed than has heretoforebeen possible by hand methods.

rent and,therefore, to give out less actinic a mask is substitutedtherefore, and t e solenoid means 37 and the plunger 38, are utilizedto'cause lever 40 therein, reversed as to position, to operate to openor close a mask A between the light 31 and the film gate aper- 1 turethereby controlling the amount of ac- 1 function as described for thosein 2 are indicated by similar reference numerals.-

tinic light reaching the films M, N, from the light 31', which in thepresent instance does not, of itself varyin brilliancy during oper-''ation.

In this last modification the parts that Obvious modifications may bemadein our device without de arting from the spirit of the invention ortl ie claims herewith appended.

Having thus described our invention, what we claim is:

1. In combination, means for feedin superposed film ast. a printinglight; a p otoelectric cell a apted to receive transmitted li ht, fromthe film to be rinted from, in advance of the printing; a xed solenoidand a source of current connected inseries with said cell; a lunger coreslidable into said solenoid and aving a collar fast on its outer endportion; a spring compressed betwwn said-collar and solenoid; a leverfulcrumed at one end and intermediately pivoted to said core; and meansoperatively engaged by the free end of said lever for varying the ac-Blithe film.

tion of the printing light- A 2. In combination, a film gate having alight aperture at one face; means for continuously feeding developed andunexposed film in superposed position through the film gate with thedeveloped film adjacent to the light aperture; a printing lam oppositeto the aperture; a housing enclosing said lamp and aperture; a sensinglamp housing having an aperture adjacent to the developed film; asensing lamp therein; a cell casing having an aperture adjacent to thefilm and registering with the aperture of the sensin lamp housing on theopposite side of the %lm; a photo electric cell in said casing adaptedto receive thereon rays from the sensing lamp passing through theadjacent apertures and film; a fixed solenoid and a source of currentconnected in series with said cell; a plunger core slidable into saidsolenoid and having a collar fast on its outer end portion; a springcompressed between said collar and solenoid; a lever fulcrumed at one.end and intermedia'tely pivoted to said core; and means operativelyengaged by the free end of said lever for varying the action-of thelight of the printinglamp substantially evenly all the way acrossthefilm transverse to the path of igs. 1 and a 3. In combination, a filmgate having a light a rture at one face; pairs of supply and ta e upreels ;at the receivin and is charge sides of the gate res from. thesupply ree and feedin them in superposed position through the 'f'igpntetov the ta e u reels, with the developed adjacent to t e light aperture;a printing lamp opposite to the aperture; a housing enclosing said lampand aperture a sensing ped a sensing lamp'therein; a cell casing havingan aperture adjacent to the film and registering with the aperture ofthe sensing lamp housing on the opposite side of the film; a photoelectric cell in said casing adapted to receive thereon ra s from thesensing lamp passing through t e adjacent apertures and film;a fixedsolenoid and a source of current connected in series with said cell; alunger core slidable into said solenoid and having a collar fast on itsouter end portion; a spring com ressed between said collar and solenoid;a eve'r fulcrumed at one end and i'ntermediately pivoted to said core;and means operatively engaged by the free end of said lever for varyingthe action of the light of-the printing lamp.

4. In combination, means for feedin superposed film ast a printinglight; a p otoelectric cell a a ted to receive transmitted light fromthe fi to be printed from in advance of the printing; a fixed solenoidand a source of current connected in series with said cell; a plungercore slidabl'e in said solenoid; resilient means between said lunger andsaid solenoid; a lever fulcrume end and intermediately pivoted to saidcore; and means operatively engaged by the free tive y; means forguiding a develo d an unexposed fil'n'i amp housineg havipfinan apertureadjacent to the deat one end of said lever for varying the action of theprinting light.

Signed at New York in the county of New York and State of New York this2nd day of May A. D. 1927. 1

- JOSEPH R. MALCOLM.

JOHN L. SPENOE, JR.

